Telephone-exchange system.



II. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JAN. 16. I9I5.

Patented Dec. 2%, 1918.

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- ZDlIflFf-Nflfs, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent. Patented Dec. 24, 1918.

Application filed January 16, 1915. Serial No. 2,553.

T 0 all whom z'tmag) concern:

Be it known that I, HENRY P. GLAUSEN, a-citizen of the United States, residing at Mount Vernon, in the county of Vestchester and State of- New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the ,following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems of the central energy type, the object of this invention being to. provide improved signaling means for such systems.

In accordance with one feature of this invention, means are provided at the central oflice whereby when conversation between two connected subscribers is'concluded and the receivers have been restored to the switchhooks. the calling subscriber may, by removing the receiver from the switchhook, cause the operation of recall signaling means at the central ofiice, notifyingthe operator that the calling subscriber desires another connection, and means are also provided at the central ofiice whereby when conversation between two connected subscribers is concluded and the receivers have been restored to the switchhooks, the called subscriber may, by removing the receiver from the switchhook, disconnect his line from the link circuit apparatus and cause the operatioigof the usual line signal associated therewit This invention is illustrated in the accompanying drawing in which all apparatus is shown in its normal and unactuated condition. i

There is shown in the drawing a telephone exchange system containing one embodiment of this invention and comprising the usual subscribers stations A and B and a cord circuit C located at a central oflice for interconnecting the subscribers stations. It is believed that this invention will be fully understood from a description of the operation of the system shown in the drawing,

and it will be so described.

Supposing subscriber A wishes to converse with subscriber B. A removes his receiver from the switchhook. thereby completing a. circuit from battery through'one winding of line relay 7 contact 8 of cutofi relay 9, line wires 10 and 11, contact 12 of cutoff relay 9 and the other winding of line relay 7 to battery 5. Current in this path actuates line relay 7 completing a circuit for line signal 13. The operator observing the line signal 13. inserts her answering plug in the jack indicated by signal 13, and thereby completes acircuit from the pole of battery 14, through contact 15 of relay '16, supervisory signal 17, resistance 18, sleeve contacts 19 and 20 of the answering plug and jack and the winding of cutofi relay '9 to ground. Current in this path actua-tes the cutoff relay 9 which severs the circuit of the line relay 7 eflacingthe line-signal 13. The insertion of the answering plug also completes a circuit from battery 25, through one winding of relay 26, conductor 27, ring contacts 28 and 29 of the answering plugand jack, line wires 10 and 11, tip contacts 30 and 31 of the jack and answering plug. conductor 32 and the other winding of relay 26 to battery 25. Current in this path actuates relay 26, opening contact 33 thereof which removes the shunt circuit from resistance 1S and preventing the operation of supervisory signal 17. Actuation of relay 26 also closes contact 34. completing a circuit from the live pole of battery 35. through contact 34 of relay 26. contact 36 of relay 37. winding of relay 38, sleeve contacts 19 and 20 of theanswering plug and jack and winding of critofi relay 9 to ground. Current in this path actuates relay 38, connecting operators telephone set 39 across tip and ring strands 40 and 41 of'the cord circuit and opens contact 42. The operator now asks the desired number of the calling subscriber. Finding the desired number to be that of subscriber B, the operator touches the tip of the calling plug to the sleeve of a jack corresponding to Bs line to determine the idle or busy condition thereof. If the line tests idle, the calling plug is inserted in the jack. completing a circuit from the live pole of battery 50, through winding of relay 37, contact 52 of relay 53. sleeve contacts 54 and 55 of calling plug and jack and winding of cutoff relay 56. to ground. Current in this path a tuates cutofi" relay 56 cutting line relay 57 from line wires 58 and 59 and actuates relay 37. which opens contact 36, thereby releasing relay 38 and disconnecting the operators telephone set 39 from the cord circuit, and

of calling plug and jack, and winding of cutofi relay 56 to ground, operating supervisory signal 64. To signal subscriber B,

the operator now depresses a button of locking ringing key 68 to which is connected a" source of ringing current of the frequency to which ringer 69 at station 18 is tuned, and in so doing closes anon-locking way-down contact 70. completing a circuit from the 15 live pole of battery 35, through contact 34 of relay 26, contact of relay 37, winding of relay 71, and contact 70 to ground. Current in this path actuates relay 71, .complet ing a locking circuit therefor through contact 72 thereof, contact 73 of marginal relay 74'to ground,'a'nd7'opening'contacts 75 and 76 and closing contacts 77 and 78. Opening of contacts 75 and 76 opens tip and ring cord conductors 40 and 41 and closure of contacts 77 and'78 connects ringing current to one side of the line and ground to the other side. The path for ringing current may be traced from ringing key 68, through relay 74, contact 78 of relay 71, cont-act 80 of relay 53, ring contacts 81 and 82 of calling plug andl jack, line' wire 58, condenser 82, ringer 69, line wire :59, tip contacts 83 and 84 ofthe jack and .callingplug, contact 85 of relay 53 and contact 77 of relay 71. to ground. ,Relay'74 is marginal and will not operate when in series with ringer 69 and condenser 82, but will operate when the relay and condenser are shunted by low resistance." The called subscriber upon removing his receiver --from the 'switchhook, closes a path of low resistance for the ringing current, thereby permitting a greater flow ofcurrent through the relay- 74. Relay 74 is thereby-actuated, opening the circuit of relay71 at contact 73 of relay 74. Relay 71 thereupon releases, removing ringing current from the line and closes the tip and ringconducto'rsof the cord circuit, completing the talking circuit. The release of relay 71 closes a circuit from battery 86,

through one winding of relay 67, conductor -41, contact 76 of relay 71, contact 80 of relay- 53, ringingcontacts 81 and 82 of calling plug and jack, line wires 58 and 59, tip contacts 83 and 84 of jack and. calling plug,

contact 85 of relay 53, contact 75 of relay 71.

' conductor 40 andlother winding of relay 67- to battery 86. Current 1 in this path actuates relay 67, opening contact 66, removing the short circuit from about resistance 87 signal 64, and

Upon finishing the conversation, subscribers A and B restore their respective receivers to the switchhooks, whereupon relays 26 thereof.

assess"? and 67 release, permitting supervisory signals 17 and 64 to operate to give disconnect signals. If the operator is not busy, the answering and calling plugs are removed from the jacks and all apparatus returns to normal. Suppose, however, that, as is frequently the case during busy periods, the operator does not immediately take down the connection, and suppose further that subscriber A desires to immediately make another call, he removes his receiver from the switchhook, thereby causing supervisory signal 17 to intermittently flash, signifying to the operator that subscriber A desires another connection. The manner in which supervisory signal 17 is caused toflash will now be described. When the receivers, were restored to the switchhooks upon .-the completion of the conversation, a circuit was completed from the live pole of battery 100, through contact 61' of relay 37, winding of relay 101, winding of relay '10'2, contact 42 of relay 38, contact 33 of relay 26, sleeve contacts 19 and 20 of answering plug amtv scriber A to make a recall (another call) causes relay 26 to be actuated over thecircuit hereinbefore traced. Actuation of re.- lay'26 opens contact 33 and closescontact 1'08 completing a circuit from the livepole of batteryl09, through contact 104 of relay 101, winding of'relay 16, contact 108 of relay 26, contact 107 of relay 102, sleeve contacts 19 and 20 of-answering plug and jack and winding of cu-toif relay 9 to ground. Current in this path actuates relay 16, closing contact 110 and opening contact 15 Closing of contact 110 completes a circuit from the live pole of battery 111. through interrupter 112, contact 110 of relay 16, supervisory signal 17, contact 107 of relay 102, sleeve contacts 19 and 20 of answering plug and'jack, and winding of cutoff relay 9 to ground, causing supervisory signal 17 to flash intermittently to furnish. a recall signal. ,The operator observing that supervisory signal 17 is flashing and that supervisory signal 64 is glowing steadily, removes the calling plug from the jack corresponding to the line of subscriber B, which causes relays 37, 101, 102, and 16 to release, vand efi'acesf supervisory signals 17 and 64. The release of relay 37 closes the hereinbeforetracedr circuit for relay 38 which is thereupon actuated, connecting the operatorstelephone set-across the conductors 40 and 41 in the manner hereinbefore explained. The operator now communicates with subscriber A and completes the desired eration of the associated line signal.

aaeaear connection in the manner already explained. It will be observed that should the receiver of subscriber B be kept oil the switchhook and the receiver of subscriber A be restored to and then removed from the switchhook, there will be no flashing of supervisory signal 17, for the circuit of relay 16 cannot be completed due to the short circuit at contact 89 of relay 67 about relay 101 .which controls the battery supply to the winding of relay 16. However, should this condition arise, and should the receiver of subscriber B then be restored'to the switchhook, relay 101 will be operated, completing the circuit of relay 16 which 'will thereupon be operated too fast to permit the proper operation of the supervisory relay, hence the supervisory signal doesnot flash. By the use of a telephone exchange-system embodying the present invention, with the foregoing conditions, subscriber B may make a call by simply replacing and then removing the receiver from the switchhook in the usual manner, causing Bs line to'be disconnected from the connecting circuit apparatus and the op- The -' manner in which this is accomplished will now be described. As before described, when the receivers are restored to the switchhooks. relays 26 and 67 are released and relays 101 and 102. are operated. Now subscriber B removes the receiver from the switchhook, completing the hereinbefoi'e traced circuit through relay 67, causing the operation of this relay. The actuation of relay 67 completes a circuit from the live pole of battery 50, through winding of relay 37, resistance 87, contact 88 of relay 67, contact 105 of relay 101 and winding115 of relay 53 to ground. Current in this path actuates relay 53 which opens contacts 52. and and closes contact 116 and 117 thereof, the closure of contact 116 completing a locking circuit for relay 53 from the live pole of battery 50, through winding of relay 37, contact 116 and winding 118 of relay 53, sleeve contacts 19 and 20 of an swering plug and jack and winding of cutoff relay 9 to ground. The opening of contacts 52. 80 and 85 opens tip. ring and sleeve conductors of the cord circuit, disconnecting all apparatus thereof from the line of subscriber B, and causing cutofi relay-56 to release which thereupon closes contacts 119 and 120 thereof. Line relay 57 is thereupon actuated completing the circuit of line signal 121. The closing of contact 117 of relay 53 completes a circuit from the live pole of battery 125, through contact 117 of relay 33, contact- "75 of relay 71, conductor 10 and one winding of relay 67 to ground, maintaining relay 67 actuated to keep supervisory signal 61 operated to furnish a disconnect signal, the circuit therefor being from the live pole of battery 65, through supervisory signal 6-1, contact 88 of relay 67, contact 105 of relay 101 and winding 115 of relay 53, to ground. Since the line signal 121 is operated, this call from subscriber B is handled in the usual manner. It is to be observed, however, that the operation of relay 53 is dependent upon the callingsubscriber having replaced the receiver on the switchhook. If the receiver of the calling subscriber has not been restored to the switchhook before the called subscriber recircuited by the path from battery 11, through contact 15 of relay 16, contact 106 of relay 102 and contact 108 of relay 26,

so that when the called subscriber B re- .moves the receiver from the switchhook -to make a call, the circuit including winding 115 of relay 53 will be open at contact of relay 101, thereby preventing the operation of relay 53.

In accordance with the present invention,

the calling subscriber may make another call after the called subscriber has made a call and while the plugs ofthe cord circuit, are

(still in the jacks of these two subscribers.

turn connects battery 111 and interrupter 112 in circuit with supervisory signal 17. This device thereupon flashes, manifesting a recall signal. The operator observing the flashing of signal 17 removes the calling plug from the jack of the line of the called subscriber, but the signals 17 and 61 will not he released because relays 37 and 53 are locked up through the sleeve contacts of the answering plug and jack. The operator then removes the answering plug from the jack and releases all apparatus associated with the cord circuit, and then re-inserts the answering plug, whereupon the relay 38 is actuated, connecting the operators telephone set 39 with the cord circuit. The operator now communicates with the calling subscriber and completes the connection in the manner already described. 5

. ductors 2i'1aiidfll ot the cord circuit which:

form the ftalkingstrandsthereof are joined through condensers 130 and 131 respectively which prevent flow of signaling currents from one endiof thecord circuit tothe other;

4 llhile only one calling and one called subscribers lifne is "shown for the sake of simplicity, it iS JtoEbe understood that many such lines will terminate at the central'othce and that each line will be multiple-d through the various sections of the switchboard. While in this description many batteries have been referred to, it is to be understood that a common battery may be substituted therefor. and such is the usual practice.

What is claimed is:

1. ln a telephone exchange system, calling and called subscribers lines, a link circuit, switching means for connecting said link circuit with said lines, recall signaling means permanently associated with one end of said link circuit, means associated with the opposite end of said link circuit for disconnecting said link circuit from the line without disturbing the switching means, and means under the joint control of the calling and called subscribers for controlling the operation of said recall signaling means and said disconnecting means.

2. In a telephone exchange system, calling and called subscribers lines. a link circuit, switching means for connecting said link circuit with said lines, flashing recall signaling means associated with the answering end of the link circuit. means associated with the calling end of said link circuit for disconnecting said link circuit from the called line without disconnection of the switching means, means controlled by the restoration to the switchhooks of both receivers and af subsequent removal of the calling subscribers receiver for operating said recall signalmg means, and means controlled by the restoration to the switchhooks of both subscribers receivers and] a subsequent removal of the called subscribers receiver for operating said disconnecting means.

3. In a telephone exchange system, calling and calledsubscribers lines, a link circuit,

switching means for connecting said link circuit with said lines, an operators teleceivers and a subsequent removal of the callmg subscribers receiver to operate said recall sial while said link it is conswitching'meansffor connecting said interrupter mechanism in said 2 v means nected with the calling line, and means controlled only. by'the disconnection of the link circuit-from the called subscribers line for petting a second operation of the switching means for connecting the operators telephone set with the talking strands of said link circuit. 1 r V At, In a telephone exchange system, calling and calledsubscribers lines, a link circuit,

circuit with 'saidflinesga supervisory signal associa-with each end of, said link circuit, interrupter-means associatedv with the answering endot said link circuit and operated upon the restoration to the switchhooks of both subscribers receivers'and a subsequent removal of the calling subscribers receiver to intermittently close the circuit of the supervisory signal associated with the answering end of said link circuit, means associated with the calling end of said link circuit and operated upon the restoration to the switch hooks of both subscribers receivers and a subsequent removal of the called subscribers receiver to disconnect the link circuit from the called subscribers line without disconnection'ot the switching means, and means for maintaining the supervisory signal associated with the calling end of the link circuit operated after the operation'of said disconnecting means.

5. In a telephone exchange system, calling and called subscribers lines, a circuit for interconnecting said lines, a relay associated with said link circuit and adapted to be controlled'from one of the connected substations. a signaling device associated with said link circuit and'controlled by said relay, interrupter mechanism, and a second relay controlled from both connected substations and operated through contacts on the first mentioned relav for connecting said interrupter mechanism in circuit with said signaling device.

6. In a telephone exchange system, cag

'and'called subscribers lines, a link circuit for interconnecting sald lines, a supervisory signal associated with saidlink circuit, a relay associated with said link circuit and adapted to be controlled from one of the connected substations, a second relay energized upon the deenergization of said first mentioned relay and locked up over a circuit completed by the energization thereof, an energizing circuit for said supervisory signal independent of said first mentioned relay, completed upon the energization of said second relay, interrupter mechanism, d a third relay, energizedby the restoration to the switchhook ot the receiver at the other cocted substation when said first mentioned relay is energized, for inclu circuit.

a telephone EX can .-.f arm Milan-1 by said relay, interrupted mechanism, and a second relay jointly controlled from both connected substations and operated through contacts on the first mentioned relay for connecting said interrupter mechanism in circuit with said signaling device.

8. In a telephone exchange system, calling and called subscribers lines, a link circuit for connecting the lines, a signaling device individual to and in the link circuit, in-

terrupter mechanism serving when in circuit with the signaling device to cause intermittent operation thereof, and means jointly controlled by the operator in connecting the link circuit with the called line and the. restoration to and the subsequent removal from its hook of the receiver at the calling station for including the interrupter mechanism in circuit with the signaling device.

9. In a telephone exchange system, calling and called subscribers lines, a link circuit connected with the calling line, a signaling device associated with the link circuit, interrupter mechanism, a relay conditioned for operation when the link circuit is con-' nected with a called line and operated upon the restoration of the receiver to the switchterrupter mechanism in circuit with the sig-.

hook by the calling subscriber, and a second relay operated upon the subsequent removal of the receiver from the switchhook by the calling subscriber for including. the interrupter mechanism in circuit with the signaling device.

10.,v In a telephone exchange system, subscribers lines, a link circuit having one end connected to a subscribers line, a supervistory relay associated with the link circuit and controlled from a connected substation, a signaling device, interrupter mechanism, a primary relay conditioned for operation upon the connection of the other end of the link circuit with another subscribers, line and operated upon the denergization of the supervisory relay, and a secondary relay operated upon the subsequent energization of the supervisory relay to include the innaling device.

11. In a telephone exchange system, cing and called subscribers lines, a link circuit connecting said lines, a supervisory relay, a signaling device, interrupter mechanism,'and a relay conditioned for operation upon the deenergization or" the supervisory. relay and operated upon the subsequent enerthereof to connect the interrupter ;'j sy,

Iii

ing and called subscribers lines, a link circuit connecting said lines, a circuit, a signaling device and interrupter mechanism adapted to be serially included in said circuit,- and means controlled by the restoration to and the subsequent removal from its hook of the receiver at the calling station for completing the circuit through the interrupter mechanism and the signaling device.

13. In a telephone exchange system, calling and called subscribers lines, a link circuit for interconnecting said lines, a signaling device and interrupter means associated-with the answering end of said link circuit, and a normally short-circuited relay for connecting said signaling device and said interrupter means in circuit, the restoration to the switchhook of the calling subscribers with a terminal for connecting said telephone line with said link circuit, a signal for said link circuit placed under substation control responsive to such connection, means responsive to an actuation of said substation switch to cause an perating circuit to be closed through said signal, means responsive to the disconnection of the link 1 0 circuit from'fthe said line circuit to interrupt said signal circuit, and means responslve'to a single actuation of said substation switch prlor to such dlsconnectlon to cause an intermittent operation of said super- 1 'visory signal.

15. In a telephone exchange system, a telephone line, a link circuit connected therewith, a supervisory relay for the link circuit, a, signaling device, an operating circuit therefor established upon the deenergization of thesupervisory relay, interrupter mechanism, and a relay conditioned for operation upon the deenergization of the supervisory relay and actuated upon the subsequent energization thereof to connect the interrupter mechanism in circuit with the signaling device to cause the intermittent operation thereof.

16. In a telephone exchange system, a are. 12o phone line, a-link circuit connected therewith, a supervisory relay for the link circuit, a signaling device, an operating circuit therefor established upon the deenergization of the supervisory relay, interrupter mechanism, a relay conditioned for operation upon the deenergization of the super visory relay and operated upon the suhsesent energization thereof, and a second operating circuit for the signaling device estion thereof to phone line, a link circuit connected therewith, a supervisory relay for the link cir cuit, a signaling device, an operating circuit therefor established by the deenergization of the supervisory relay, a second operating circuit for the signaling device, interrupter mechanism in the second operating circuit, and a relay conditioned for operation upon the cleenergization of the supervisory relay and operatetll upon the suhsequent energizaopen the second operating circuit.

18. In a telephone. exchange system, a; tele- -phone line, a circuitconnected there first, and close the means? with, a supervisory relay fo the link circuit, a signaling device, an operating circuit therefor established upon the deenergization of the supervisory relay, a normally ineffective intermittent operating circuit for the signaling device, a second relay ener gizecl upon the deenergizat-ion of the supervisory relay, and a third relay operating while the supervisory and second relays are energized to render the first operating cir-' cuit inefiecti e and the second efiective.

In witness whereof, ll hereunto suhscrihe my name this 15th day of January A. D.

HENRY 1P. CLAUSEN. Witnesses E. En 1 K. L. fine. 

